If you want to use Metamask with MEW, you can export your private key from your MEW wallet and import it into Metamask. If you do export your private key, please do not post the private key anywhere online. Anyone with the private key can simply empty all your funds in the associated address.
On Seed Words and Wallet Recovery
Each wallet has a different method of encrypting your private keys in that wallet. The seed words regenerate the private keys in the wallet. Here’s an explanation. It’s written for bitcoin, but it applies pretty much the same to all seed word algorithms.
So, if you have a wallet that uses 24 seed words and I have a wallet that uses 12 seed words, the regeneration algorithm is different, but the private keys created will be compatible.
Please note: If the recovery seed words are entered, the regenerated private keys replace the contents of the current wallet. So, if you have a wallet that has some funds in it, and enter in the recovery seed words from another wallet, the current private keys will be deleted and replaced with the recovered keys.
The simplest definition of a cold wallet is a private key that is inaccessible from the blockchain network.
Examples of cold wallets:
- Paper Wallet
- Hardware Wallet
Any wallet solution that allows you to export the private keys can be converted from a hot wallet to a cold wallet. Simply export the private keys, print them out on paper… DON’T LOSE THE PAPER … remove or overwrite the hot wallet private keys for that address on your system, and you’ve got a cold wallet.
There are some online websites that generate a nicely formatted paper wallet. I don’t trust them… never enter your private key anywhere except in a wallet application you know well and have checked for trustworthiness.
Of course, there are some security folks who would also remove the memory module of the printer you used and smash that too… but I don’t think that’s necessary.
There are several tutorials online about printing out a private key and a public key. This is not necessary for Ethereum addresses. The public key and Ethereum address are algorithmically generated from the private key. It’s not a split key system like PGP. However, if you don’t know the public address of the wallet, you won’t know where to send incoming funds.
Personal Recommendation on Wallet Use
Any funds that you wouldn’t cry over for a year if lost them somehow, can be safely kept in a generic wallet application. If you want to exchange funds from one token to another, transfer the funds to a Metamask address and use Uniswap. Then transfer the funds back… or just import the private keys into Metamask. You can remove the private keys after the transaction is complete if you are worried about later compromise of your browser.
All wallets, except for a paper wallet, are subject to electronic theft of some kind. There are vulnerabilities in all software… and hardware wallets can also be compromised.
The only “safe” way to use Ethereum and ERC-20 tokens is to generate all keys and transactions offline and send the transactions to mainnet later. This can only be accomplished if one is running a local Ethereum node… which is extremely resource intensive.
I use and trust Metamask and Atomic Wallets. MEW is pretty much the same as Atomic Wallet. These three are fairly safe and quite well tested.
- Ethereum Keys, Understanding Blockchain Keys Basis
- PGP RFC4880
- How to use My Ether Wallet generator offline